Oracle字符串截取和拼接应用

今天有人问了个关于Oracle字符串截取和拼接的问题，让我帮他写出SQL，看了下问题描述还比较清晰就试着解决下，利用午休时间把功能实现了，问题看似不难，但思路一定要清晰，不然就乱了，关键大量应用了Oracle的substr 和instr函数，下面贴出问题和脚本： 问

今天有人问了个关于Oracle字符串截取和拼接的问题，让我帮他写出SQL，看了下问题描述还比较清晰就试着解决下，利用午休时间把功能实现了，问题看似不难，但思路一定要清晰，不然就乱了，关键大量应用了Oracle的substr 和instr函数，下面贴出问题和脚本：

问题：sql中一个字段值为：1788987565327、768374872394903、21437238740213483874629、23412341234252345。其中顿号间隔的每一组数字位数和尾数不定，现在要使前面这个字段值中顿号前的数字尾数即7、3、9、5都分别加1，变成8、4、0、6输出成1788987565328、768374872394904、21437238740213483874620、23412341234252346。注意其中第三个数，从9加1后，输出成0，而不是10

脚本：

declare
    targetstr varchar2(2000);
    strlength number;
    position number;
    maxposition number;
    retrunstr varchar2(2000);
    tempstr varchar2(2000);
    endstr number;
begin
    targetstr := '1788987565327、768374872394903、21437238740213483874629、23412341234252345';
    maxposition := 0;
    select LENGTH(targetstr) into strlength  from dual;
    for i in 1..strlength loop
        select instr(str,'、',1,i) into position from （select targetstr as str from dual）;
        --dbms_output.PUT_LINE(position);
        if position > 0 then
            if maxposition = 0 then
                select substr(str,0,instr(str,'、',1,1)-1) into retrunstr from （select targetstr as str from dual）;
                select TO_NUMBER(substr(restr,-1)) into endstr from （select retrunstr as restr from dual）;
                if endstr = 3 or endstr = 5 or endstr = 7 then
                    endstr := endstr + 1;
                elsif endstr = 9 then
                    endstr := 0;
                end if;
                select substr(str,0,instr(str,'、',1,1)-2)||TO_CHAR(endstr) into retrunstr from （select targetstr as str from dual）;
            elsif maxposition < position then
                select substr(str,instr(str,'、',1,i-1)+1,instr(str,'、',1,i)-instr(str,'、',1,i-1)-1) into tempstr from （select targetstr as str from dual）;
                select TO_NUMBER(substr(restr,-1)) into endstr from （select tempstr as restr from dual）;
                if endstr = 3 or endstr = 5 or endstr = 7 then
                    endstr := endstr + 1;
                elsif endstr = 9 then
                    endstr := 0;
                end if;
                select substr(str,1,length(str)-1) ||TO_CHAR(endstr) into tempstr from （select tempstr as str from dual）;
                retrunstr := retrunstr || '、'|| tempstr;
            end if;
            maxposition := position;
        else
            if maxposition > position then
                --特别处理最后一段
                tempstr := '';
                select substr(str,maxposition-length(str)) into tempstr from （select targetstr as str from dual）;
                select TO_NUMBER(substr(restr,-1)) into endstr from （select tempstr as restr from dual）;
                if endstr = 3 or endstr = 5 or endstr = 7 then
                    endstr := endstr + 1;
                elsif endstr = 9 then
                    endstr := 0;
                end if;
                select substr(str,1,length(str)-1) ||TO_CHAR(endstr) into tempstr from （select tempstr as str from dual）;
                retrunstr := retrunstr || '、'|| tempstr;
            end if;
            exit;
        end if;
    end loop;
    dbms_output.PUT_LINE(retrunstr);
end;

运行结果如下：

原字符串：1788987565327、768374872394903、21437238740213483874629、23412341234252345

14:03:38  **** SCRIPT STARTED: 02-Apr-2015 14:03:38 ****
14:03:38  declare
14:03:38      targetstr varchar2(2000);
14:03:38  ...
14:03:39  PL/SQL block executed
1788987565328、768374872394904、21437238740213483874620、23412341234252346
14:03:39  **** SCRIPT ENDED 02-Apr-2015 14:03:39 ****
14:03:39  End Script Execution